Redwoods absorb moisture in the fog through their leaves, preserving ground water during dry summers.
A decline in California’s famed coast fog over the past century could threaten the survival of the endangered coast redwood forests, which depend on the misty low clouds for a good portion of their water supply.
James A. Johnstone of the University of California, Berkeley found that the duration of fog cover along the coast during summer has dropped about three hours per day since 1901.
The fog duration reached its all-time low in 1997.
Johnstone says this is due to a reduction in temperature differences between the ocean and interior, which normally pulls the fog into a narrow coastal strip at night through early mornings during summer.
Since the towering redwoods absorb fog moisture in their leaves, the fog bank reduces the amount of groundwater the trees need during the normally rain-free California summers.
Less fog threatens that relationship.
Photo: Nathaniel Frey - iStockphoto